1. Field of the Invention
The present invention relates to air conditioners for vehicles and, more particularly, to an air conditioner for vehicles having a two layer flow structure, designed to feed recirculation air and fresh air in a separate air feeding or a mixed air feeding using a single intake duct and a single intake control door, thus improving its heating and defrosting efficiency during a heating mode operation, and preventing an undesired discharging of white fogging from the vents during a cooling mode operation by changing its air feeding mode from a recirculation air mode to fresh air feeding mode.
2. Description of the Prior Art
FIG. 10 is a view, showing the construction and operation of a conventional air conditioner for vehicles. As shown in the drawing, the conventional air conditioner for vehicles typically comprises a cooling unit and a heating unit, either of which is selectively operated as desired. In an operation of the conventional air conditioner in a cooling mode, a compressor 61 is operated by the rotating force of the internal combustion engine (not shown) of a vehicle to compress refrigerant prior to feeding the compressed refrigerant to a condenser 62. At the condenser 62, ambient air forcibly fed from a cooling fan (not shown) absorbs heat from the refrigerant, thus condensing and cooling the refrigerant. The condensed refrigerant from the condenser 62 then passes through a receiver dryer 63, an expansion valve 64, and an evaporator 65 sequentially prior to being returned to the compressor 61, thus accomplishing one refrigeration cycle. During the above-mentioned refrigeration cycle, pressurized air fed from the fan 661 of a blower unit 66 passes by the evaporator 65 while losing heat to the cold refrigerant, thus becoming cooled air prior to being discharged from the housing of the air conditioner into the passenger compartment of the vehicle. In an operation of the air conditioner in a heating mode, the pressurized air fed from the fan 661 of the blower unit 66 is heated by hot coolant passing through a heater core 67 when the hot coolant is returned to the engine through the heater core 67. During the heating mode, the air is thus heated prior to being discharged from the housing of the air conditioner into the passenger compartment, while the coolant is cooled prior to being returned to the engine.
In such a conventional air conditioner, both the evaporator 65 and the heater core 67 are set within the housing 7 of the air conditioner. The blower unit 66 is installed inside the air inlet end of the housing 7 at a position in front of the evaporator 65, while three air outlet vents: a defrost vent 71, a face vent 72 and a floor vent 73 are provided in the air outlet end of the housing 7 at positions in back of the heater core 67. Of the three air outlet vents, the defrost vent 71 discharges warm or cold air from the housing 7 to the windshield and side glasses of the vehicle, thus defrosting the windshield and side glasses. The face vent 72 discharges warm or cold air from the housing 7 to the upper portion inside the passenger compartment, thus heating or cooling the upper portion of the compartment. The floor vent 73 discharges warm or cold air from the housing 7 to the lower portion of the passenger compartment, thus heating or cooling the lower portion of the compartment. A vent control door 711, 712 or 731 is installed at each of the three air outlet vents 71, 72 and 73 to control the vents as desired.
In the conventional air conditioner, both a fresh air intake opening 663 and a recirculation air intake opening 664 are respectively formed on the upper portion of the blower case 662 of the blower unit 66 at opposite sides of the case 662, with one intake control door 665 hinged to the case 662 such that the door 665 selectively closes either of the two air intake openings 663 and 664 as desired. Therefore, when only fresh air is introduced into the housing 7 through the fresh air intake opening 663 to circulate the fresh air in the passenger compartment during an operation of the air conditioner, the compressor 61 is undesirably overloaded to excessively consume power of the engine. On the other hand, when only recirculation air is introduced into the housing 7 through the recirculation air intake opening 664 to circulate the recirculation air in the passenger compartment during an operation of the air conditioner, the circulated air within the passenger compartment is gradually reduced in its freshness to become contaminated, thus ill-affecting the passenger""s health. When the intake control door 665 is positioned at its neutral position to allow fresh air and recirculation air to be mixed together, the recirculation air included in the mixed air is continuously discharged into the passenger compartment during an operation of the air conditioner, thus preventing the passengers from feeling freshness of the fresh air and forcing the passengers to feel unpleasant.
In an effort to overcome such problems experienced in the conventional air conditioner for vehicles, another air conditioner designed to feed recirculation air and fresh air into the passenger compartment in a separate air feeding or a mixed air feeding, has been proposed.
Japanese Patent Laid-open Publication No. Heisei. 9-24722 discloses an example of such air conditioners. This air conditioner has three air intake openings, with two intake control doors used for controlling the flow of recirculation and fresh air through the three intake openings. However, this air conditioner is problematic in that it requires too many parts, inducing a complex construction, due to the complex mechanism for operating the intake control door.
Another example of such air conditioners may be referred to Japanese Patent Laid-open Publication No. Heisei. 9-24723. This air conditioner has first and second air intake openings designed to selectively recirculation or fresh air, in addition to a third air intake opening used for intaking recirculation air exclusively, with two intake control doors used for controlling the flow of recirculation and fresh air through the three intake openings. However, this air conditioner is problematic in that it requires too many parts, inducing a complex construction, due to the complex mechanism for operating the intake control door in the same manner as described above.
A further example of such air conditioners may be referred to Japanese Patent Laid-open Publication Nos. Heisei. 9-156348 and Heisei. 10-16539. Each of these air conditioners has one fresh air intake opening and two recirculation air intake openings, with two intake control doors used for controlling the flow of recirculation and fresh air through the three intake openings. In addition, Japanese Patent Laid-open Publication Nos. Heisei. 9-240247, Heisei. 9-240248 and Heisei. 10-86637 each disclose an air conditioner having one recirculation air intake opening, one fresh air intake opening, and two intake control door of the sliding type used for controlling the flow of recirculation or fresh air through the recirculation air intake opening and the fresh air intake opening. This air conditioner also has one recirculation air intake opening controlled by a separate intake control door. As further prior art reference documents, Japanese Patent Laid-open Publication Nos. Heisei. 10-915 and Heisei. 10-86637 each disclose an air conditioner having one recirculation air intake opening and one fresh air intake opening with one intake control door used for controlling the flow of recirculation or fresh air through the recirculation air intake opening and fresh air intake opening. This air conditioner also has one recirculation air intake opening controlled by a separate intake control door.
However, the above-mentioned air conditioners are problematic in that they have two intake control doors for controlling the flow of recirculation and fresh air relative to the housing, with a link mechanism for accomplishing a cooperative operation of the intake control doors, thus necessarily having too many parts and a complex construction.
Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide an air conditioner for vehicles, which is designed to feed recirculation and fresh air in a separate air feeding or a mixed air feeding using a single intake duct and a single intake control door, thus improving its heating and defrosting efficiency during a heating mode operation, and preventing an undesired discharging of white fogging from the vents during a cooling mode operation by changing its air feeding mode from a recirculation air mode to a fresh air mode, and which preferably is simplified in its construction, in addition to being reduced in its production cost.
In order to accomplish the above object, the present invention provides an air conditioner for vehicles. The air conditioner comprises a housing, a partition member, a first heat exchanger , a first blower fan and a second blower fan. The housing defines a chamber and the chamber defines first and second openings configured to allow first and second air flows to enter an inside of the chamber, respectively. The partition member is configured to divide the inside of the housing into first and second passages. The partition member extends through the inside of the chamber and is configured to divide the chamber into first and second compartments. The first heat exchanger is configured to pass through an opening in the partition member so as to be located in the first and second passages. The first blower fan is located in the first compartment of the chamber and is configured to blow at least one of the first and second air flows to the first heat exchanger along the first passage. The second blower fan is located in the second compartment of the chamber and is configured to blow at least one of the first and second air flows to the first heat exchanger along the second passage.
According to the invention, a communication vent opened or closed by a vent control door is preferably formed at the rear portion of the horizontal partition wall to allow the upper and lower air passages to communicate to each other selectively.
In a fresh air mode operation of the heating, the intake control door closes the recirculation air intake opening of the intake duct. Therefore, only fresh air is introduced into the intake duct through the fresh air intake opening, and flows into both the upper and lower scroll compartments through the air guide duct, and flows through the upper and lower air passages prior to being discharged into the passenger compartment.
In a recirculation air mode operation of the air conditioner, the intake control door closes the fresh air intake opening of the intake duct. Therefore, only recirculation air is introduced into the intake duct through the recirculation air intake opening, and flows into both the upper and lower scroll compartments through the air guide duct, and flows through the upper and lower air passages prior to being discharged into the passenger compartment.
In a separate air feeding operation of the air conditioner, the intake control door is aligned with the passage dividing means, thus allowing the recirculation and fresh air intake openings of the intake duct to separately communicate with the lower and upper scroll compartments through the air guide duct. Therefore, fresh air and recirculation air separately flow through the upper and lower air passages prior to being separately discharged from the housing into the passenger compartment.
In a mixed air feeding operation of the air conditioner, the intake control door is positioned at a space between the passage dividing means and the fresh air intake opening. Therefore, recirculation air from the recirculation air intake opening flows to both scroll compartments, while fresh air from the fresh air intake opening only flows to the lower scroll compartment. Mixed air of the recirculation air and the fresh air from the upper scroll compartment flows through the upper air passage prior to being discharged into the passenger compartment, while recirculation air from the lower scroll compartment flows through the lower air passage prior to being discharged into the passenger compartment.